Passive Entity Issue

I don't know what is the cause of these masses spawning in a 360 degree ring from where my outpost is but they do. You can follow all the mobs in a complete circle and see masses. I've never really experienced such an issue previously at other outpost but I am having odd spawns here and it despawns some of my animals at the animal pens within the outpost because of these ring spawn animals. I kill these non stop but they come back shortly within the hour. What can be causing such catastrophic spawns?

This happens at my iron farm, Ill come back & found huge clumps of them around the outside of my walls and I just end up killing them all off

I said to Chicken in the PM coz I didn't want eyes to begin looking for this area if I mentioned that there is 2 inactive gold farms here. I haven't used them since the issue started. Began to lower frame rates not only for myself but TPS began to drop. I've since left the outpost until today thinking that the issue might have fixed itself overtime with some code revamps from Aikar in the past few months. I come back today and the entities have doubled their masses. I cannot keep up with their spawning as it is superior in the speed I can kill them at.

for mine my alt just sits out in the middle of nowhere at my farm with the villagers spawning & iron golems spawning. I dont know if maybe the animals spawn in because I flattened & lit up the land but normally Ill come back to the entc limit sometimes